// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/files/file_enumerator.h"
#include "base/files/file_util.h"
#include "net/disk_cache/blockfile/block_files.h"
#include "net/disk_cache/disk_cache.h"
#include "net/disk_cache/disk_cache_test_base.h"
#include "net/disk_cache/disk_cache_test_util.h"
#include "testing/gtest/include/gtest/gtest.h"

using base::Time;

namespace {

// Returns the number of files in this folder.
int NumberOfFiles(const base::FilePath& path)
{
    base::FileEnumerator iter(path, false, base::FileEnumerator::FILES);
    int count = 0;
    for (base::FilePath file = iter.Next(); !file.value().empty();
         file = iter.Next()) {
        count++;
    }
    return count;
}

} // namespace

namespace disk_cache {

TEST_F(DiskCacheTest, BlockFiles_Grow)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    const int kMaxSize = 35000;
    Addr address[kMaxSize];

    // Fill up the 32-byte block file (use three files).
    for (int i = 0; i < kMaxSize; i++) {
        EXPECT_TRUE(files.CreateBlock(RANKINGS, 4, &address[i]));
    }
    EXPECT_EQ(6, NumberOfFiles(cache_path_));

    // Make sure we don't keep adding files.
    for (int i = 0; i < kMaxSize * 4; i += 2) {
        int target = i % kMaxSize;
        files.DeleteBlock(address[target], false);
        EXPECT_TRUE(files.CreateBlock(RANKINGS, 4, &address[target]));
    }
    EXPECT_EQ(6, NumberOfFiles(cache_path_));
}

// We should be able to delete empty block files.
TEST_F(DiskCacheTest, BlockFiles_Shrink)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    const int kMaxSize = 35000;
    Addr address[kMaxSize];

    // Fill up the 32-byte block file (use three files).
    for (int i = 0; i < kMaxSize; i++) {
        EXPECT_TRUE(files.CreateBlock(RANKINGS, 4, &address[i]));
    }

    // Now delete all the blocks, so that we can delete the two extra files.
    for (int i = 0; i < kMaxSize; i++) {
        files.DeleteBlock(address[i], false);
    }
    EXPECT_EQ(4, NumberOfFiles(cache_path_));
}

// Handling of block files not properly closed.
TEST_F(DiskCacheTest, BlockFiles_Recover)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    const int kNumEntries = 2000;
    CacheAddr entries[kNumEntries];

    int seed = static_cast<int>(Time::Now().ToInternalValue());
    srand(seed);
    for (int i = 0; i < kNumEntries; i++) {
        Addr address(0);
        int size = (rand() % 4) + 1;
        EXPECT_TRUE(files.CreateBlock(RANKINGS, size, &address));
        entries[i] = address.value();
    }

    for (int i = 0; i < kNumEntries; i++) {
        int source1 = rand() % kNumEntries;
        int source2 = rand() % kNumEntries;
        CacheAddr temp = entries[source1];
        entries[source1] = entries[source2];
        entries[source2] = temp;
    }

    for (int i = 0; i < kNumEntries / 2; i++) {
        Addr address(entries[i]);
        files.DeleteBlock(address, false);
    }

    // At this point, there are kNumEntries / 2 entries on the file, randomly
    // distributed both on location and size.

    Addr address(entries[kNumEntries / 2]);
    MappedFile* file = files.GetFile(address);
    ASSERT_TRUE(NULL != file);

    BlockFileHeader* header = reinterpret_cast<BlockFileHeader*>(file->buffer());
    ASSERT_TRUE(NULL != header);

    ASSERT_EQ(0, header->updating);

    int max_entries = header->max_entries;
    int empty_1 = header->empty[0];
    int empty_2 = header->empty[1];
    int empty_3 = header->empty[2];
    int empty_4 = header->empty[3];

    // Corrupt the file.
    header->max_entries = header->empty[0] = 0;
    header->empty[1] = header->empty[2] = header->empty[3] = 0;
    header->updating = -1;

    files.CloseFiles();

    ASSERT_TRUE(files.Init(false));

    // The file must have been fixed.
    file = files.GetFile(address);
    ASSERT_TRUE(NULL != file);

    header = reinterpret_cast<BlockFileHeader*>(file->buffer());
    ASSERT_TRUE(NULL != header);

    ASSERT_EQ(0, header->updating);

    EXPECT_EQ(max_entries, header->max_entries);
    EXPECT_EQ(empty_1, header->empty[0]);
    EXPECT_EQ(empty_2, header->empty[1]);
    EXPECT_EQ(empty_3, header->empty[2]);
    EXPECT_EQ(empty_4, header->empty[3]);
}

// Handling of truncated files.
TEST_F(DiskCacheTest, BlockFiles_ZeroSizeFile)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    base::FilePath filename = files.Name(0);
    files.CloseFiles();
    // Truncate one of the files.
    {
        scoped_refptr<File> file(new File);
        ASSERT_TRUE(file->Init(filename));
        EXPECT_TRUE(file->SetLength(0));
    }

    // Initializing should fail, not crash.
    ASSERT_FALSE(files.Init(false));
}

// Handling of truncated files (non empty).
TEST_F(DiskCacheTest, BlockFiles_TruncatedFile)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));
    Addr address;
    EXPECT_TRUE(files.CreateBlock(RANKINGS, 2, &address));

    base::FilePath filename = files.Name(0);
    files.CloseFiles();
    // Truncate one of the files.
    {
        scoped_refptr<File> file(new File);
        ASSERT_TRUE(file->Init(filename));
        EXPECT_TRUE(file->SetLength(15000));
    }

    // Initializing should fail, not crash.
    ASSERT_FALSE(files.Init(false));
}

// Tests detection of out of sync counters.
TEST_F(DiskCacheTest, BlockFiles_Counters)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    // Create a block of size 2.
    Addr address(0);
    EXPECT_TRUE(files.CreateBlock(RANKINGS, 2, &address));

    MappedFile* file = files.GetFile(address);
    ASSERT_TRUE(NULL != file);

    BlockFileHeader* header = reinterpret_cast<BlockFileHeader*>(file->buffer());
    ASSERT_TRUE(NULL != header);
    ASSERT_EQ(0, header->updating);

    // Alter the counters so that the free space doesn't add up.
    header->empty[2] = 50; // 50 free blocks of size 3.
    files.CloseFiles();

    ASSERT_TRUE(files.Init(false));
    file = files.GetFile(address);
    ASSERT_TRUE(NULL != file);
    header = reinterpret_cast<BlockFileHeader*>(file->buffer());
    ASSERT_TRUE(NULL != header);

    // The file must have been fixed.
    ASSERT_EQ(0, header->empty[2]);

    // Change the number of entries.
    header->num_entries = 3;
    header->updating = 1;
    files.CloseFiles();

    ASSERT_TRUE(files.Init(false));
    file = files.GetFile(address);
    ASSERT_TRUE(NULL != file);
    header = reinterpret_cast<BlockFileHeader*>(file->buffer());
    ASSERT_TRUE(NULL != header);

    // The file must have been "fixed".
    ASSERT_EQ(2, header->num_entries);

    // Change the number of entries.
    header->num_entries = -1;
    header->updating = 1;
    files.CloseFiles();

    // Detect the error.
    ASSERT_FALSE(files.Init(false));
}

// An invalid file can be detected after init.
TEST_F(DiskCacheTest, BlockFiles_InvalidFile)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    // Let's access block 10 of file 5. (There is no file).
    Addr addr(BLOCK_256, 1, 5, 10);
    EXPECT_TRUE(NULL == files.GetFile(addr));

    // Let's create an invalid file.
    base::FilePath filename(files.Name(5));
    char header[kBlockHeaderSize];
    memset(header, 'a', kBlockHeaderSize);
    EXPECT_EQ(kBlockHeaderSize,
        base::WriteFile(filename, header, kBlockHeaderSize));

    EXPECT_TRUE(NULL == files.GetFile(addr));

    // The file should not have been changed (it is still invalid).
    EXPECT_TRUE(NULL == files.GetFile(addr));
}

// Tests that we generate the correct file stats.
TEST_F(DiskCacheTest, BlockFiles_Stats)
{
    ASSERT_TRUE(CopyTestCache("remove_load1"));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(false));
    int used, load;

    files.GetFileStats(0, &used, &load);
    EXPECT_EQ(101, used);
    EXPECT_EQ(9, load);

    files.GetFileStats(1, &used, &load);
    EXPECT_EQ(203, used);
    EXPECT_EQ(19, load);

    files.GetFileStats(2, &used, &load);
    EXPECT_EQ(0, used);
    EXPECT_EQ(0, load);
}

// Tests that we add and remove blocks correctly.
TEST_F(DiskCacheTest, AllocationMap)
{
    ASSERT_TRUE(CleanupCacheDir());
    ASSERT_TRUE(base::CreateDirectory(cache_path_));

    BlockFiles files(cache_path_);
    ASSERT_TRUE(files.Init(true));

    // Create a bunch of entries.
    const int kSize = 100;
    Addr address[kSize];
    for (int i = 0; i < kSize; i++) {
        SCOPED_TRACE(i);
        int block_size = i % 4 + 1;
        EXPECT_TRUE(files.CreateBlock(BLOCK_1K, block_size, &address[i]));
        EXPECT_EQ(BLOCK_1K, address[i].file_type());
        EXPECT_EQ(block_size, address[i].num_blocks());
        int start = address[i].start_block();
        EXPECT_EQ(start / 4, (start + block_size - 1) / 4);
    }

    for (int i = 0; i < kSize; i++) {
        SCOPED_TRACE(i);
        EXPECT_TRUE(files.IsValid(address[i]));
    }

    // The first part of the allocation map should be completely filled. We used
    // 10 bits per each four entries, so 250 bits total.
    BlockFileHeader* header = reinterpret_cast<BlockFileHeader*>(files.GetFile(address[0])->buffer());
    uint8_t* buffer = reinterpret_cast<uint8_t*>(&header->allocation_map);
    for (int i = 0; i < 29; i++) {
        SCOPED_TRACE(i);
        EXPECT_EQ(0xff, buffer[i]);
    }

    for (int i = 0; i < kSize; i++) {
        SCOPED_TRACE(i);
        files.DeleteBlock(address[i], false);
    }

    // The allocation map should be empty.
    for (int i = 0; i < 50; i++) {
        SCOPED_TRACE(i);
        EXPECT_EQ(0, buffer[i]);
    }
}

} // namespace disk_cache
